Fluid pressure cylinder locking mechanism



July 22, 1941.

' J. PALMER 0 FLUID PRESSURE CYLINDER LOCKING IEOHKRISI Filed June 18, 1940 2 Shoots-Sheet. 1

Jabn a. alrnel;

July 22, 1941. J. A. PALMER FLUID PRESSURE CYLINDER LOCKING MECHANISM Filed June 18, 1940 2 Sheets-Sheet 2 Mn Q56);

Patented July 22, 1941 FLUID PRESSURE CYLINDER LOCKING MECHANISM John A. Palmer, Baltimore, Ma, assignor to The Glenn L. Martin Company, Baltimore, Md.

Application June 18, 1940, Serial No. 341,105

'IClaims.

The invention relates to fluid pressure cylinder and piston arrangements and particularly to locking mechanism therefor.

Hydraulic cylinder mechanisms are used for actuating many types a of mechanisms. Such cylinder, mechanisms are under some circum-' stances likely to undergo movement even when pressure fluid is not supplied to them.

The primary object of the present invention is to provide a hydraulic cylinder mechanism which will prevent movement of the piston from either extreme position in the cylinder unless iiuid pressure is supplied thereto.

Another object oi the invention is to provide a mechanism of this type which does not permit access oi pressure fluid to the cylinder until the locking mechanism has been released.

Further objects and advantages will appear more fully from the following description, particularly when taken in conjunction with the accompanying drawings which term a part thereof.

In the drawinss:

Fig. 1 is a side elevation, partly in section, of a hydraulic mechanism embodying the invention; m

Fig. 2 is a longitudinahsection through the head end of the hydraulic cylinder mechanism oil-1&

Fig. 3 is a cross-section principally on the line 8-2 of Fig. 2.

The invention in the form shown is applied to a hydraulic cylinder 2 having a piston I with e. piston rod '6. The head end only of the cylinder is shown in detail in Fig. 2. In the particular arrangement shown. damping means are provided for the head end of the pis-' ton stroke, composed of a projection 8 or the piston which moves into an annular projection Ill leaving only a slight space I 2 therebetween. Pressure fluid enters the cylinder through an opening il in one side thereof and flows through space l2 to adt on the face of the piston.

Opening ll communicates with the interior of a casing l6 mounted onone side of the cylinder, one of these casings being provided at each end of the cylinder. This casing has an inlet at I! to which a source of pressure fluid may be connected. The locking mechanism is arranged in this casing.

Piston l is provided on its periphery with annular V-shaped grooves l8, it. These grooves may-be engaged, in the manner shown, by looking arms 20 of latch members 22 mounted to,

turn on pivots 24 in the two casings It, so as to slldable therein 7 lock the piston at each end of its movement. Latch member 22 is provided with an arcuate rack portion 26 concentric with pivot 24.

Siidable in the casing 16 is a block 28 having a rack portion Ill meshing with rack 26. This block is urged in a direction to move locking arms 20 into engagement with notch IB, or l8 as the case may he, (to {the right in Fig. 2) by a coil spring 22 arranged between casing l6 and.

block 28. a

Block 28 has at the opposite end, near inlet II, a piston portion 24 sliding with a tight flt by packing 35 in casing I6. Portion 24 is provided with a bore 36 communicating at one end with inlet l1, and at the other end by opening 28 with the interior of easing l6. Opening 28 is normally closed by a ball valve 40 within-bore l6 pressed on its seat by a coil spring 42 which at its other end rests on a spider 44 in the mouth oi bore 26.

Secured by a threaded joint 6 in the casing it at the end opposite inlet i1 is a pin 48 which extends through a bore 50 in block 28 to a point adjacent to and in alignment with opening 28 and ball 40.

The operation of this mechanism is as follows: Normally the parts occupy. the position shown in the drawings. Piston I cannot then move outwardly (or to the left, Fig. 2) because oi the engagement of the end of locking arm 20 with the wall of groove ll.

Ii fluid under pressure is admitted to inlet II,

it flows into bore 26 and against ball 40 which of course closes opening 38. The pressure causes the whole block 28 'to move to the left,

Fig. 2, a ainst the spring 22. Racks 20, 26 upon this movement cause locking member 22 to turn counterclockwise (Fig. 2) and locking arm 20 disengages from groove Ill, leaving the piston freeto move in the cylinder.

0 As block 28 moves further to the leift, pin Iii enters aperture ill and finally ball lll' engages the end of the pin. 'This of course lifts the ball from its seat, and pressure fluid flows through opening 32, the interior of easing l6 and opening it to the hydraulic cylinder, where it engages the piston to push it to the left (Fig. 2). When thesupply of fluid under pressure ceases, spring 22 moves block 28 back .to the right, returning locking arm 20 to its locking position. When the piston is returned to its original position, the fluid can displace ball valve 40 and escape from the cylinder. As the piston moves back, groove it comes opposite. locking arm 20 which again engages in the groove, thus again locking the piston against movement.

of course the left-hand or rod end of the mechanism of Fig. 1 operates in the same manner, latch 20 engaging in groove l9 when the piston is in extended position (dotted lines in Fig. l) and locking the piston rod out until pressure fluid for moving the piston in is supplied to inlet I'i.

Threaded connection 46 makes it possible to adjust the piston of pin 48, so that the time of opening of ball valve 40 can be varied.

While I have described herein one embodiment of my invention I wish it to be understood that I do not intend to limit myself thereby ex cept within the scope of the appended claims.

I claim:

1. In combination with a fluid pressure cylinder having a piston movable therein, means to lock the piston against movement, fluid supply means connected to said cylinder, a one-way discharge valve normally closing said fluid supply means, and means operated by pressure fluid for releasing said locking means and thereafter opening said valve.

2. In combination with a fluid pressure cylinder having a piston movable therein, means to lock the piston against movement, fluid supply means connected to .said cylinder, a slidable member in said fluid supply means, means urging said member in one direction, said member moving in the other direction under the pressure 01' fluid in said supply means, a one-way discharge valve normally closing said supply means, and means operated by movement of said member in said other direction for flrst releasing said locking means and thereafter opening said valve.

3. In combination with a fluid pressure cylinder having a piston movable therein, means to lock the piston against movement, fluid supply means connected to said cylinder, a slidable member in said fluid supply means, means urging said member in one direction, said member moving in the other direction under the pressure of fluid in said supply means, a valve movably mounted in said member normally closing said supply means, and means operated by movement oi said member in said other direction for first releasing said locking means and thereafter opening said valve.

4. In combination with a fluid pressure cylinder having a piston movable therein, means to lock the piston against movement, fluid supply means connected to said cylinder, a slidable member in said fluid supply means, means urging said member in one direction, said member moving in the other direction under the pressure of fluid in said supply means, means movably mounted in said member normally closing'sald supply means, and means operated by movement or said member in said other direction for first releasing said locking means and thereafter opening said supply means, said last means including a flxed member engageable with said closing means during movement of said member to move said closing means with respect to said member.

5. In combination with a fluid pressure cylinder having a piston movable therein, means to lock the piston against movement, fluid supply means connected to said cylinder, a slidable member in said fluid supply means, means urging. said member in one direction, said member having a bore therethrough, means to supply fluid through said bore to said cylinder, a valve in said bore normally closing said supply means. whereby supply of pressure fluid to said supply means moves said member, means operated by movement of said member to release said locking means, and a stationary element mounted in the path of movement of said member engageable with said valve to open said valve when said member has released said locking means.

6. In combination with a fluid pressure cylinder having a piston moveable therein, said piston having a recess therein, a locking member movable to engage in said recess to lock said piston against movement, fluid supply means connected to said cylinder, a one-way discharge valve normally closing said fluid supply means, and means operated by pressure-fluid for releasing said locking member and thereafter opening said valve.

7. In combination with a fluid pressure cylinder having a piston movable therein, said piston having a recess therein, a locking element pivoted for movement into said recess, fluid supply means connected to said cylinder, 9. slidable member in said fluid means, means urging said member in one direction, said member having a bore therethrough, means to supply fluid through said bore to said cylinder, a valve in said bore normally closing said supply means. whereby supply or pressure fluid to said supply means moves said member, meshing gearing on said element and member whereby movement of said member in said other ection releases said looking element, and a stationary element mounted in the path of movement of said member engageable with said valve to open said valve when said member has released said locking means.

' JOHN a. PALMER. 

